How sweet is the pacemaker?

Pacemaker infections can be difficult to diagnose, especially when they present with non-specific symptoms and signs a long time after insertion of the device. Unidentified or partially treated low-grade chronic sepsis can result in multisystem disease processes with significant mortality and morbidity. Therefore, a high index of suspicion is required to identify the pacemaker as the source of sepsis and treat it effectively. This report describes a case of chronic pacemaker wire infection, which eventually presented with Sweet's syndrome, a rare manifestation of infective endocarditis.

An unusual but reversible cause of ventricular fibrillation.

A 61-year-old woman was admitted with general malaise, chest pain and breathlessness. During her inpatient stay she sustained a ventricular fibrillation (VF) arrest which was successfully terminated with direct current cardioversion. Cardiac investigations revealed poor left ventricular systolic function but unequivocally normal coronary arteries. During the course of her admission a macular rash developed and following investigations including a renal biopsy, a new diagnosis of systemic lupus erythematosus (SLE) and related myocarditis was reached. First presentation of lupus with myocarditis and VF is uncommon, however reaching the correct diagnosis is important as due to the reversible nature of the condition and improvement in left ventricular systolic function with medical therapy, an implantable cardioverter defibrillator (ICD) might not be appropriate. Our case report demonstrates the importance of screening for reversible conditions when considering ICD therapy for secondary prevention of malignant arrhythmias.

Cognitive impact of genetic variation of the serotonin transporter in primates is associated with differences in brain morphology rather than serotonin neurotransmission.

A powerful convergence of genetics, neuroimaging and epidemiological research has identified the biological pathways mediating individual differences in complex behavioral processes and the related risk for disease. Orthologous genetic variation in non-human primates (NHPs) represents a unique opportunity to characterize the detailed molecular and cellular mechanisms that bias behaviorally and clinically relevant brain function. We report that a rhesus macaque orthologue of a common polymorphism of the serotonin transporter gene (rh5-HTTLPR) has strikingly similar effects on behavior and brain morphology to those in humans. Specifically, the rh5-HTTLPR (S)hort allele broadly affects cognitive choice behavior and brain morphology without observably affecting the 5-hydroxytryptamine (5-HT) transporter or 5-HT(1A) concentrations in vivo. Collectively, our findings indicate that 5-HTTLPR-associated behavioral effects reflect genotype-dependent biases in cortical development rather than static differences in serotonergic signaling mechanisms. Moreover, these data highlight the vast potential of NHP models in advancing our understanding of human genetic variation affecting behavior and neuropsychiatric disease liability.

Repetitive genetic inversion of optical extinction data.

We describe a genetic method of deriving aerosol size distributions from multiwavelength extinction measurements. The genetic inversion searches for log-normal size distribution parameters whose calculated extinctions best fit the data. By repetitively applying the genetic inversion using different random number seeds, we are able to generate multiple solutions that fit the data equally well. When these solutions are similar, they lend confidence to an interpretation, whereas when they vary widely, they demonstrate nonuniqueness. In this way we show that, even in the case of a single log-normal distribution, many different distributions can fit the same set of extinction data unless the misfit is reduced below typical measurement error levels. In the case of a bimodal distribution, we find many dissimilar size distributions that fit the data to within 1% at six wavelengths. To recover the original bimodal distribution satisfactorily, we found that extinctions at ten wavelengths must be fitted to within 0.5%. Our results imply that many size distributions recovered from existing extinction measurements can be highly nonunique and should be treated with caution.

Mitral valve surgery in the elderly.

BACKGROUND AND AIMS OF THE STUDY: Previous studies have shown that outcome from mitral valve surgery is poorer in the elderly. However, such studies did not distinguish between age itself, age-associated factors and interactions between age and other factors. We aimed to examine the relative influences of age and these other factors on outcome. METHODS: We compared outcomes from mitral valve repair or replacement in 190 elderly (> or = 70 years) and 424 younger (< 70 years) consecutive adult patients. RESULTS: At baseline, the elderly had more (p > 0.05) degenerative mitral regurgitation, coronary artery disease, left ventricular impairment, New York Heart Association (NYHA) class III or IV symptoms, bioprosthetic replacement and mitral valve repair. Operative mortality rate was low both in elderly (7/190 patients, 3.7%) and younger patients (15/424 patients, 3.5%, NS). Seven-year survival was poorer in the elderly with respect to overall survival, (49 +/- 6% vs. 72 +/- 3%, p = 0.0001), freedom from complications-related death (57 +/- 7% vs. 79 +/- 3%, p = 0.001), from death due to myocardial failure (66 +/- 6% vs. 86 +/- 3%, p < 0.0001) and from overt myocardial failure (44 +/- 7% vs. 74 +/- 3%, p = 0.0001). Multivariate analysis showed better survival with younger age, mitral valve repair, better preoperative NYHA class and better left ventricular function. However, 7-year freedom from complications-related death was excellent and similar in both elderly (90 +/- 7%) and younger (93 +/- 3%, NS) patients who underwent surgery early while in NYHA class I or II with left ventricular ejection fraction > 40%. CONCLUSIONS: Late surgery contributes far more than age itself to poor outcome from mitral valve surgery in the elderly. If surgery is performed early and repair preferred to replacement whenever feasible, medium-term results are excellent in both young and old.